This invention relates to apparatus for boiling, cooking, steaming, simmering and sterilizing liquid, porridge-like or lumpy feeds.
It is common knowledge that foodstuffs and other materials can be continuously steamed, cooked, simmered or boiled at atmospheric pressure.
It is also known to boil and thereby to sterilize foodstuffs by heating them in a water bath to temperatures above 100.degree.C under gauge pressure. Boiling under pressure is a more rapid process for cooking than boiling at atmospheric pressure. Moreover, the higher pressure prevents water contained in the cooking material from being evaporated and the boiled food therefore remains more juicy and retains its flavor. The duration of the cooking is preferably so chosen that the material is sterilized. If the pressure is high enough to enable the temperature to be raised to 121.degree.C or more without causing the water bath to boil, any germs in the liquid as well as spores will be destroyed. In this connection reference is made to U.S. Pat. No. 1,544,304.
The drawback of processes which permit continuous operation is that they are confined to boiling at atmospheric pressure. This diminishes the quality of the cooked material.
At the same time it is a drawback of known pressure cooking processes that they do not as such admit of continuous operation as they are batch processes. In view of this fact several such batch cookers must by alternately operated in parallel if continuity is to be maintained. Naturally this involves a higher capital cost.